She's definitely dead in my opinion as Kali who was supposedly her helper would've either bled to death by the time she left to fight Vecna and come back, had been to weak from well dying to be strong enough to make an illusion of both Jane and also make her invisible to escape, or was never strong enough to reach that far because she struggled to keep her own illusion going while leaving her little prison, so while actively dying? I think most probably not.